Adriaen Thomasz Key (c. 1544, Antwerp – c. 1599, Antwerp), was a Flemish Renaissance portrait painter.
Little is known of his life. According to the Rijksmuseum, he was a pupil of his (distant) relative Willem Key. According to the RKD he became a vrijmeester, or master in the Antwerp Guild of St. Luke in 1568.